CVD of mono and double-layers on Si-B-N-C fibres

The reinforcement effects of the fibres in metal matrix composites (MMC) or ceramic matrix composites (CMC) are widely influenced by coatings acting as diffusion barriers, sliding layers or protection against oxidation. Mono layers and double-layer systems was deposited by isothermal CVD process to newly developed ceramic fibres [1] of type of quarternary ceramic Si-B-N-C. The design of continuous multi-stage deposition process and the effect of chemical composition of deposited films will be discussed. Variations of layer compositions were extensively investigated by SEM, TEM, SIMS, XPS and Raman spectroscopy. A great importance was attached to characterization of interfaces.